1. Field
The present invention relates generally to communications systems, and more specifically, to systems and techniques to generate control information for packet data transport.
2. Background
Modern communications systems are designed to allow multiple users to access a common communications medium. Numerous multiple-access techniques are known in the art, such as time division multiple-access (TDMA), frequency division multiple-access (FDMA), space division multiple-access, polarization division multiple-access, code division multiple-access (CDMA), and other similar multi-access techniques. The multiple-access concept is a channel allocation methodology which allows multiple user access to a common communications medium. The channel allocations can take on various forms depending on the specific multi-access technique. By way of example, in FDMA systems, the total frequency spectrum is divided into a number of smaller sub-bands and each user is given its own sub-band to access the communications medium. Alternatively, in TDMA systems, each user is given the entire frequency spectrum during periodically recurring time slots. In CDMA systems, each user is given the entire frequency spectrum for all of the time but distinguishes its transmission through the use of a unique code.
CDMA is a modulation and multiple access technique based on spread-spectrum communications. In a CDMA communications system, a large number of signals share the same frequency spectrum. This is achieved by transmitting each signal with a different code that modulates a carrier, and thereby, spreads the spectrum of the signal waveform. The transmitted signals are separated in the receiver by a demodulator that uses a corresponding code to despread the desired signal""s spectrum. The undesired signals, whose codes do not match, are not despread in bandwidth and contribute only to noise.
The use of CDMA techniques for multiple access communications generally provides increased user capacity over traditional TDMA and FDMA techniques. As a result, more users can access a network, or communicate with one another, through one or more base stations. In CDMA systems, the channel allocations are based on orthogonal sequences known as Walsh codes. Depending on the particular communications application, any number of Walsh code channels may be needed to support various control channels such as the pilot channel and other commonly used control channels. These control channels tend to consume system resources, and thereby, decrease user capacity by reducing the resources available to process traffic. With the tremendous increase in wireless applications over the past years, there is a need for a more efficient and robust control channel methodology which reduces computational complexity to maximize user capacity by allocating more system resources to traffic.
In one aspect of the present invention, method of communications includes transmitting a data packet over at least one time slot from a transmission site, computing a value from an initial value and information, the initial value being a function of the number of time slots of the data packet transmission, transmitting the value and the information from the transmission site, receiving the transmitted value and the information at a receiving site, recalculating the value from the received information, and determining the number of time slots of the data packet transmission from the calculated and recalculated values.
In another aspect of the present invention, a communications system includes a base station having a channel element configured to generate a data packet extending over at least one time slot and compute a value from an initial value and information, the initial value being a function of the number of time slots of the data packet, and a transmitter configured to transmit the data packet, the value and the information, and a subscriber station having a receiver configured to receive the value and the information from the base station, and a processor configured to recalculate the value from the received information and determine the number of time slots of the data packet from the calculated and recalculated values.
In yet another aspect of the present invention, a transmitting device includes a channel element configured to generate a data packet extending over at least one time slot and compute a value from an initial value and information, the initial value being a function of the number of time slots of the data packet, and a transmitter configured to transmit the data packet, the value and the information.
In a further aspect of the present invention, a receiving device includes a receiver configured to receive a data packet transmitted over at least one time slot, and a value and information, the value being computed from an initial value and the information, the initial value being a function of the number of time slots of the data packet transmission, and a processor configured to recalculate the value from the received information, and determine the number of time slots of the data packet transmission from the calculated and recalculated values.
In yet a further aspect of the present invention, a computer-readable media embodying a program of instructions executable by a computer program performs a method of communications, the method including generating a data packet extending over at least one time slot, computing a value from an initial value and information, the initial value being a function of the number of time slots of the data packet, and formatting the data packet, the value, and the information for transmission over a communications medium.
In another aspect of the present invention, a communications system includes a base station having means for generating a data packet extending over at least one time slot and means for compute a value from an initial value and information, the initial value being a function of the number of time slots of the data packet, and means for transmitting the data packet, the value and the information, and a subscriber station having means for receiving the value and the information from the base station, means for recalculating the value from the received information, and determination means for determining the number of time slots of the data packet from the calculated and recalculated values.
In yet another aspect of the present invention, a transmitting device includes means for generating a data packet extending over at least one time slot, means for computing a value from an initial value and information, the initial value being a function of the number of time slots of the data packet, and means for formatting the data packet, the value and the information for transmission over a communications medium.
In a further aspect of the present invention, a receiving device includes means for receiving a data packet transmitted over at least one time slot, and a value and information, the value being computed from an initial value and the information, the initial value being a function of the number of time slots of the data packet transmission, means for recalculating the value from the received information, and determination means for determining the number of time slots of the data packet transmission from the calculated and recalculated values.
It is understood that other aspects of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein is shown and described only exemplary embodiments of the invention, simply by way of illustration. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modifications in various respects, all without departing from the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.